Such a flexible pipe is for example made according to the normative documents API 17J (Specification for Unbonded Flexible Pipe) and API RP 17B (Recommended Practice for Flexible Pipe) established by the American Petroleum Institute.
The pipe is generally formed with a set of concentric and superposed layers. It is considered as unbounded in the sense of the present invention from the moment that at least one of the layers of the pipe is able to move longitudinally with respect to the adjacent layers during flexure of the pipe. In particular, an unbonded pipe is a pipe without any binding materials connecting layers forming the pipe.
In a known way, such a pipe includes a tubular internal structure comprising at least one pressure sheath. The pipe includes layers of tensile armor positioned around the tubular internal structure.
The pipe further includes, in certain cases, a pressure volt, formed with at least one stapled wire for example having a T-profile or a Z-profile. A fret may also be spirally wound around the pressure volt.
The abrasive material is collected at the bottom of the extent of water for example within the scope of a mining operation of an underwater bottom, or further during excavation work of underwater soils with view to setting into place facilities for producing hydrocarbons. The abrasive material for example comprises rocks and/or sediments.
In particular, the abrasive material is formed with mining aggregates disaggregated by underwater excavatory cutting machines. These aggregates are notably obtained from massive sulfide deposits (designated by the term of Seabed Massive Sulfides or SMS) containing traces of metals, notably of copper, of lead, of zinc, of gold, of silver or of other metals.
In certain cases, these materials are located at significant depths, sometimes greater than several hundred meters. Within this scope, WO 2009/013434 describes a device for extracting materials comprising a pipe of the aforementioned type giving the possibility of bringing back the material from the extraction facility located at the bottom of the extent of water towards the surface.
The recovered material at the bottom of the extent of water is sometimes highly abrasive and generates significant wear of the transport pipe, notably by cutting wear mechanisms or by gouging wear mechanisms.
In order to ensure the conveyance of the abrasive material towards the surface, it is therefore necessary to have a flexible pipe which has good mechanical strength, notably in traction and in pressure, and which also has excellent resistance to abrasion, considering the size and the aspect of the mining aggregates to be brought to the surface, for a period of time which may attain several years, or even several tens of years.